Sea cliff at Glowe: stratigraphy and absolute age chronology of the Jasmund Pleistocene sedimentary record (original) (raw)
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Weichselian glacial stage in Murchisonfjorden, Nordaustlandet, Svalbard
Boreas, 2009
Compared to the other islands in the Svalbard archipelago, Nordaustlandet offers only limited stratigraphical or sedimentological information on its Quaternary deposits. This article aims to fill the gap by presenting new results from glacial geological, sedimentological and chronological studies in the southern Murchisonfjorden area. Field data include reconnaissance mapping and detailed logging of vertical sections along cliff-face outcrops a few metres high adjacent to the present-day shoreline. Combined with OSL and AMS age determinations, these data provide evidence of three successive Weichselian sequences, each represented by the deposition of till followed by the accumulation of shallow marine deposits. Contrary to earlier conclusions, this study demonstrates that the area was occupied by a Late Weichselian glacier (LWG), although the LWG till is thin and discontinuous. Interstadial sublittoral sand related to the Mid-Weichselian interstadial was dated to 38–40 kyr, and an Early Weichselian interstadial to 76–80 kyr. The preservation of older sediments, multiple striae generations and abundant observations of weathered local bedrock material indicate weak glacial erosion within the study area. We suggest that the Late Weichselian glacier was relatively inactive and remained mainly cold-based until the deglaciation. The Isvika sections can be considered a new key site that offers further potential to improve our understanding of the Weichselian stage within the northwestern sector of the Barents–Kara Ice Sheet.
GFF, 2006
Conventional Optically Stimulated Luminescence (OSL) dating using the equivalent dose distributions of 8 mm aliquots have been extended to key stratigraphical sites in southernmost Sweden and the island of Bornholm. The objective has been to bridge the lack of an independent chronology, which might catalyze a new understanding of the ice flow patterns related to the initiation of the Last Glacial Maximum, and the stratigraphical development during the deglaciation sequence. Sediments from proximal environments are usually 10-15 kyr older than expected from regional stratigraphical correlations and radiocarbon dates of mammoth tusks. We propose that OSL signals are inherited from reworked sediments that were sufficiently bleached prior to glacial or glaciofluvial transportation and deposition. Sediments from distal and beach environments seem to indicate proper depositional ages. Thus, the main Weichselian stadial was preceded by almost 20 kyr of ice free conditions, succeeded by an ice advance from south-southeast before northeasterly ice flow predominated. Major inconsistencies still exists for the final deglaciation. Two distinct environmental reconstructions of the uppermost diamict at two separate sites, both superimposed on a periglacial surface, predict either deposition during subaquatic conditions associated with drifting icebergs after 16 kyr or subglacial sedimentation associated with an ice advance in Öresund. It remains unsolved whether the periglacial surface at the two sites can be correlated or if they represent two different stratigraphical levels. In perspective, the introduction of OSL dates in Skåne has identified the periglacial marker horizon or horizons as targets for future intensive dating.
Boreas, 2008
Fourteen lake basins on and west of Mt. Billingen have been analysed with respect to different stratigraphic methods: pollen, diatoms, other microfossils, I4C datings, lithology, grain-size distribution and chemical characteristics. The aim has been to establish a well-dated pollen stratigraphy for the area in order to date when lakes west of Mt. Billingen were raised above sea level. Previous studies and results from the area have also been included in the study. Distance diagrams, with different tilting directions, have been constructed. A shore displacement curve from c. 11,300 to c. 9,300 B.P., based on the most probable tilting direction, shows a complex uplift picture. A rather low regression gradient (U d 1 0 0 years) during c. 1, OOO years was, at c. 10,200 B.P., followed by a distinctly increasing gradient (8-9 d100 years) followed by a marked gradient decrease at c. 9,500 B.P. The latter was possibly caused by a distinct sea level transgression on the Swedish West Coast. Indications of a short transgression around 10,ooO B.P. as well as the possibly complicated course of isolation of Lake Vanern from the sea are also discussed. Finally the shore displacement is related to the deglaciation of the area and the supposed two drainages of the Baltic Ice Lake.
Journal of Quaternary Science, 1999
Mineral magnetic properties and the carbon content of a sediment sequence in Lake Kullatorpssjö n on the Kullen Peninsula in northwest Scania, southern Sweden, were investigated. Diatom and ostracod analyses were undertaken for palaeoecological reconstruction and a chronology was constructed from accelerator mass spectrometry (AMS) radiocarbon dating of terrestrial plant remains and mosses. Five stratigraphical units were identified (units 1-5, from oldest to youngest). The two lowermost units consist of clay. The lowest clay unit (1) is strikingly black, 2 m thick and has magnetic properties dominated by high concentrations of authigenic greigite (Fe 3 S 4 ). In contrast, the overlying clay unit (2) is grey, 1.18 m thick and has magnetic properties dominated by low concentrations of detrital magnetite (Fe 3 O 4 ). A major palaeoecological change is reflected in the diatom flora and ostracod fauna at the transition from unit 1 to unit 2. The sediment stratigraphy, geochemical, mineral magnetic and palaeoecological analyses also point to a significant change in depositional environment at this transition, which is proposed to represent the isolation of Lake Kullatorpssjö n from the Kattegat Sea. Earlier investigations have determined the marine limit to ca. 65 m a.s.1. on the Kullen Peninsula. The separate independent lines of evidence presented here, however, suggest that the Late Weichselian marine limit developed at 85-90 m a.s.l. at the deglaciation ca. 17 200 cal. yr BP (ca. 14 500 yr BP). This limit is ca. 25 m higher than assumed previously. Lake Kullatorpssjö n formed ca. 1000 cal. yr later when the basin became isolated from the Kattegat Sea.
Polar Research, 1995
Late Weichselian to early Holocene sedimentation in a steep fjord/valley setting, Visdalen, Edgeoya, eastern Svalbard: glacial deposits, alluvial/colluvial-fan deltas and spit-platforms PER MOLLER. OLE P. STUBDRUP and CHRISTIAN KRONBORG Moller, P.. Stubdrup, 0. P. & Kronborg. C. 1995: Late Weichselian to early Holocene sedimentation in a steep fjord/valley setting, Visdalen. Edgeeya, eastern Svalbard: glacial deposits, alluvial/colluvial-fan deltas and spit-platforms. Polar Research 14(2), 181-203.
2004
During the last decades, our understanding of the Weichselian glaciation history of southern Fennoscandia has become progressively more complex as new data have become available, i.e. Larsen & Sejrup (1990), Houmark-Nielsen (1999), Sejrup et al. (2000), Olsen et al. (2001) and Mangerud (In press). Long and continuous records from the deep sea and from the Greenland Ice Sheet have been especially important in understanding the Weichselian climate changes in the North Atlantic region. Oxygen-isotope records from Greenland ice-cores indicate several rapid climate shifts during the Weichselian (Dansgaard et al. 1993). These oscillations have been correlated to changes recorded in North Atlantic marine sediments (Bond et al. 1993; Fronval et al. 1995; Haflidason et al. 1995; Elliot et al. 2001) and terrestrial sediments from western Norway (Olsen et al. 2001; Mangerud et al. 2003), suggesting a closely coupled ocean-atmosphere system in the Northern Atlantic region during the Weichselian.
Boreas, 2009
The Quaternary sedimentary succession in Vendsyssel, northern Denmark, contains a unique, high-resolution record of the last interglacial and glacial periods. There is still much debate, however, about the timing and ice extent in this southwestern part of the Scandinavian Ice Sheet, particularly during the Middle Weichselian. In this study, a detailed lithostratigraphical subdivision is established for the Late Saalian to Middle Weichselian Skaerumhede Group on the basis of numerous, up to 250 m deep, boreholes in Vendsyssel. The sediments mainly consist of marine clays, glaciolacustrine sediments and tills, and the total thickness of the Skaerumhede Group is up to 140 m. Marine intervals have been used as stratigraphical marker units to separate the formations indicative of ice-sheet activity in Vendsyssel, and the timing of the events has been constrained by a large number of optically stimulated luminescence (OSL) and radiocarbon ages. The Skaerumhede Group is subdivided into seven formations and two members, reflecting shifts between marine and terrestrial sedimentation caused by fluctuations of the Scandinavian Ice Sheet and changes in sea level. The lowermost Skaerumhede Till Formation was deposited directly on top of the bedrock during the Warthe advance c. 160-140 kyr BP. Above, there are fine-grained marine sediments, subdivided into the Lower, Middle and Upper Skaerumhede Clay Formations. The marine formations are separated by the Brønderslev Formation related to the Sundsøre ice advance from the north c. 65-60 kyr BP, and the Å sted Formation, deposited during the Ristinge advance from an east-southeastern direction c. 55-50 kyr BP. The uppermost formation in the group is the Lønstrup Klint Formation, which is an upwards-coarsening sequence of mainly glaciolacustrine sediments deposited prior to the Kattegat advance c. 30-29 kyr BP. The new evidence from Vendsyssel has shown that the Skaerumhede Group covers a large area, and that it can be used as a regional stratigraphical marker horizon. Furthermore, it contributes to a better understanding of the timing and extent of glacial events during the Late Saalian to Middle Weichselian in southwest Scandinavia.